The present invention relates in general to decorating technology applicable to cylindrical articles using direct rotary printing of compositions in various predetermined patterns and registrations. Still more particularly, the present invention is directed to an apparatus and method for decorative direct rotary printing of various cylindrical articles such as glassware and the like with radiation curable compositions such as ultraviolet radiation (UV) and the like.
In the glassware decorating industry, there exists the desire to apply one or more layers of a suitable material in various predetermined patterns to an article for decorative or other purposes. One of the important commercial applications today is in the printing of bottles having a generally cylindrical configuration. The term xe2x80x9ccylindricalxe2x80x9d as used herein is intended to cover articles, e.g., bottles, which have at least one portion which is characterized by a cylindrical cross-sectional shape, e.g., substantially circular or round. The aforementioned bottles have found a wide variety of applications, for example, cosmetics, perfumes, food products, household and personal cleansing products, etc. One application which is believed to dominate the present market in terms of volume is beverage bottles for both soft and alcoholic beverages.
There is known a variety of apparatuses for decorating bottles with multiple colored printing inks for forming decorative predetermined patterns and/or textured material. For example, it has been common practice to decorate cylindrical shaped bottles using a screen printing apparatus which includes a conventional reciprocating screen or squeegee printing assembly. In the known reciprocating screen printing assembly, a generally rectangular frame supports a patterned screen which carries the printing ink to be screen printed onto the underlying article by means of a squeegee. In one such type of screen printing assembly, the screen is held stationary while the squeegee is moved across the surface of the screen in order to force the printing ink through the screen thereby creating the desired pattern. In another screen printing assembly, the screen is reciprocated laterally while maintaining the squeegee stationary in engagement with the surface of the screen. Illustrative of the aforementioned screen printing assembly are those disclosed in Poo, et al., U.S. Pat. No. 4,068,579; Walker, U.S. Pat. No. 4,091,726; Eldred, et al., U.S. Pat. No. 4,263,846; Lala, U.S. Pat. No. 4,282,806; Cammann, U.S. Pat. No. 4,352,326; Okura, U.S. Pat. No. 4,380,955; Combeau, U.S. Pat. No. 4,434,714; Heidenreich, U.S. Pat. No. 5,317,967; Carlyn, et al., U.S. Pat. No. 5,343,804; and Strutz, et al., U.S. Pat. No. 5,524,535.
In addition to the aforementioned reciprocating screen printing assemblies, there is known from Von Saspe, U.S. Pat. No. 3,933,091 a screen printing apparatus employing a stationary semi-circular printing screen using a rotatable squeegee assembly having a plurality of squeegees. There is further known from Coningsby, U.S. Pat. No. 4,628,857, a screen printing apparatus including a horizontally arranged rotary screen printing assembly. The screen printing assembly is operative for printing a non-continuous coating on a substrate of various shapes such as cylindrical, conical or oval, in particular, slender-like articles such as writing implements. The screen printing assembly is in the nature of a cylindrical hollow printing drum provided with an opening for accommodating a patterned screen. The interior of the drum includes a squeegee and a supply of printing ink. Articles to be screen printed are placed on a conveyor and moved to a position underlying the screen at which time the article is lifted by an elevator mechanism into engagement with the continuously rotating screen printing drum.
In Duce, U.S. Pat. No. 4,885,992 there is disclosed a vertically arranged indirect rotary screen printing assembly particularly adapted for printing spark plug insulators. The screen printing assembly includes a vertically arranged screen printing drum provided with a printing screen and an internal squeegee. The screen is arranged in contact with a transfer roller having a transfer surface. The image to be transferred is first applied to the transfer surface and, upon rotation of the transfer roller, to the surface of the intended article such as the spark plug insulator. The use of a vertical screen printing assembly avoids having to index articles to be printed from an initial vertical supply orientation to a horizontal printing orientation, and then back again to a vertical discharge orientation. Other bottle screen printing apparatuses are known from Helling, U.S. Pat. No. 5,471,924 and Strauch, et al., U.S. Pat. No. 4,005,649.
The economics of the bottle screen printing industry are directly related to production rate. Conventional reciprocating screen printing assemblies are known to achieve production rates of only about 180 bottles per minute. In the lucrative beverage bottle decorating industry, it is desirable to obtain production rates of at least 250 bottles per minute, and preferably 500-700 bottles per minute, and optimally up to 1000 bottles per minute. These production rates cannot be achieved by the aforementioned reciprocating screen printing assemblies. In addition, the conventional reciprocating screen printing assemblies, due to their stroke length, e.g., up to about 36 inches, occupy a substantial space within the screen printing apparatus. As a result, the space provided for curing the screen printed ink is often inadequate, rendering the aforementioned screen printing apparatus generally undesirable for multi-colored screen printing operations where curing may be desired between screen printing workstations, and in particular, where high production rates are desired. This becomes more significant when screen printing multiple registered layers of a printing ink which requires overprinting of one layer with the next layer without the adverse consequences of streaking of the previously applied layer.
In Von Saspe, production rates of up to 220 bottles per minute are disclosed using the stationary semi-circular screen printing assembly. However, the screen printing apparatus of Von Saspe requires multiple drying tunnels which occupy a large portion of the screen printing apparatus, and hence, floor space which might not always be available.
A number of the aforementioned disadvantages from the known screen printing apparatus are overcome by the screen printing apparatus disclosed in U.S. Pat. No. 5,985,376, and assigned to the same assignee of the present application, the disclosure of which is incorporated herein by reference. The disclosed reciprocating screen printing apparatus arranges a UV radiation source opposing the printing screen at each screen printing workstation. Articles to be decorated are positioned between the UV radiation source and the printing screen. Each article is printed with an image formed from a UV curable composition by being rolled across the printing screen. The UV radiation source is positioned so that as the applied image is transferred to the article, UV radiation is incident upon the article""s surface as it rolls away from the printing screen with the newly transferred image. The image is exposed to the UV radiation for a sufficient duration such that a cured skin forms on the surface of the transferred image of sufficient strength to support the next layer to be applied to the article. The disclosed screen printing apparatus has a production rate of up to about 180 bottles per minute.
Notwithstanding the known screen printing apparatus, there remains a need for further improvements in printing apparatuses and decorating methods therefore which are operable for printing, for example, UV curable compositions, in various patterns and/or registered layers directly onto articles having cylindrical portions at a production rate heretofore unknown from the prior art, while at the same time, allowing for the at least partial cure of the radiation curable composition between one or more screen printing workstations. By way of example, such improvements are disclosed in U.S. patent application Ser. No. 09/166,811, filed on Oct. 6, 1998 and assigned to the same assignee of the present invention, the disclosure of which is incorporated herein by reference.
The rotary screen printing assembly of the present invention differs from the reciprocating shuttle-type screen printing assemblies in that the printing screen rotates, as opposed to shuttling back and forth in a horizontal plane. This enables the rotary screen printing assembly to occupy a smaller space within the apparatus, as well as to provide increased production rates.
In accordance with one embodiment of the present invention there is disclosed an apparatus for printing a layer of radiation curable material onto individual articles having a cylindrical surface. The apparatus includes a rotary printing assembly operative for directly printing a layer of radiation curable material onto the cylindrical surface of individual articles. The rotary printing assembly includes a rotationally supported belt defining an interior region, the belt having a planar portion for contact with the cylindrical surface of the articles for directly printing a layer of the radiation curable material thereon. At least one squeegee is arranged within the interior region of the belt having a portion engaging the belt for contacting the planar portion of the belt with the cylindrical surface of the article. The squeegee in the preferred embodiment is moveable longitudinally within the interior region of the belt during the printing operation. A radiation emitting device can be positioned adjacent the rotary printing assembly for at least partially curing the layer of radiation curable material applied to the articles. The articles are transported by a transporting assembly into operative relationship with the rotary printing assembly and the radiation emitting device. The transporting assembly includes a plurality of fixtures for releasably securing the articles and which are operative for rotating the articles when at least in operative association with the planar portion of the rotary printing assembly.
In accordance with another embodiment of the present invention there is disclosed a process for directly applying a layer of radiation curable material onto individual articles having a cylindrical surface. The process includes conveying the articles into operative association with a rotary printing assembly including a rotationally supported belt defining an interior region, the belt having a planar portion for contact with the cylindrical surface of the articles for directly printing a layer of radiation curable material thereon. At least one squeegee within the interior region of the belt engages the belt for contacting the planar portion of the belt with the cylindrical surface of the article. The squeegee in the preferred embodiment is moveable longitudinally within the interior region of the belt during the printing operation. The articles are rotated when in operative contact with the planar portion of the belt, while directly printing a layer of radiation curable material from the planar portion of the belt onto the cylindrical surface of the articles. The printed layer on the articles is exposed to radiation sufficient to at least partially cure the printed layer.
An apparatus for printing a layer of material onto individual articles having a curved surface, the apparatus comprising a rotationally supported printing belt in the shape of a loop, the belt having an inner surface defining an interior region, a rotationally supported squeegee belt in the shape of a loop within the interior region, and at least one squeegee attached to the squeegee belt, the squeegee having a distal portion in operative association with the inner surface of the printing belt adapted for printing the material onto the surface of the articles.
An apparatus for direct rotary printing a layer of radiation curable material onto a curved surface of individual articles, the apparatus comprising a continuous loop shaped printing belt having an inner surface defining an interior space and an outer surface arranged in a vertical plane, a printing belt drive assembly for rotating the printing belt, a continuous loop shaped squeegee belt arranged within the interior space, a squeegee belt drive assembly for rotating the squeegee belt, the printing belt and the squeegee belt each having a planar portion opposing one another in spaced apart relationship, a source of radiation curable material in communication with the interior space, at least one squeegee attached to the squeegee belt, the squeegee having a distal end in operative association with the source of radiation curable material for transferring the material to the inner surface of the printing belt.
An apparatus for direct rotary printing a layer of radiation curable material onto a cylindrical surface of individual articles, the apparatus comprising a continuous loop shaped printing belt having an inner surface defining an interior space and an outer surface defining a printing surface, the outer surface oriented in a vertical plane for engagement with the cylindrical surface of the individual articles; a printing belt drive assembly for rotating the printing belt including a printing belt drive and a printing belt follower arranged in spaced apart relationship, and a motor for rotating the printing belt drive whereby the printing belt is rotated; a continuous loop shaped squeegee belt arranged within the interior space, the printing belt and the squeegee having planar portions opposing one another in spaced apart relationship; a squeegee belt drive assembly for rotating the squeegee belt including a squeegee belt drive and a squeegee belt follower arranged in spaced apart relationship, and a motor for rotating the squeegee belt drive whereby the squeegee belt is rotated; a source of radiation curable material arranged in communication with the interior space; at least one squeegee attached to the squeegee belt, the squeegee having a distal end in operative association with the source of radiation curable material for transferring the material to the inner surface of the printing belt for printing by the printing surface.
A process for applying a material in a pattern onto individual articles having a curved surface, the process comprising conveying the articles into operative association with a rotationally supported printing belt having a planar portion for contact with the curved surface of the articles for applying the material thereon, supplying material to the printing belt for application onto the articles, rotating the articles when in operative contact with the planar portion of the belt, rotating at least one squeegee having a path of travel along the planar portion of the printing belt, and applying the layer of material from the planar portion of the belt onto the curved cylindrical surface of the articles upon contact of the squeegee with the planar portion of the printing belt.
A process for applying a rotation curveable material in a predetermined pattern onto individual articles having a cylindrical surface, the process comprising conveying the articles into operative association with a rotationally supported loop-shaped printing belt having a planar printing portion for contact with the cylindrical surface of the articles for applying the material thereon in the pattern, supplying material to an inner surface of the printing belt opposing the pattern for application onto the articles, rotating the articles when in operative contact with the planar printing portion of the printing belt, rotationally supporting at least one squeegee on a loop shaped squeegee belt having a planar portion opposing the planar printing portion, rotating the at least one squeegee by the squeegee belt, the squeegee having a distal end having a path of travel in contact with the planar printing portion of the printing belt, and applying the material from the planar printing portion of the printing belt onto the cylindrical surface of the articles upon contact of the squeegee with the inner surface of the planar printing portion of the printing belt.